I've been thinking about this since yesterday, but I really don't think you've provided an argument that supports this claim.

If we establish the freedom to believe and do anything you want (as I've proposed), then anything that you might believe or do as part of your religion would be a subset of that, and would have the same protections. You don't need to say the word "religion", with all the ambiguity and assumptions that that word invites.

That said, I do recognize that my proposed wording speaks more to the freedom of religious practice, as opposed to the freedom from religious discrimination.

But we still need not introduce the words "religion", "god", or "spiritual". If, for example, we say that the government can't discriminate or show preferential treatment based on any idealogical leanings, personal habits, or social or ethnic ties, then I think that would cover it. That would implicitly forbid discrimination on anything that religious membership entails, plus it would offer protection for people whose religious communities may be small or new enough not to be recognized as such.